The present invention relates to a system for transmitting the power of an engine of a four-wheel drive vehicle to front and rear wheels, and more particularly to a system for a four-wheel drive vehicle having an automatic transmission and a central differential.
A full time four-sheel drive vehicle having a central differential is well known. In such a vehicle, a differential lock system is provided for preventing the front or rear wheels from skidding. As a differential lock system, a dog clutch device operated by a pneumatic actuator is widely used.
However, if the actuator is operated when the vehicle is stopped or at cornering, the dog clutch does not engage unless the actuator is operated at the time when corresponding dogs coincide with each other. Further, it frequently happens that the clutch engages after some delay under particular driving conditions.